Catalytic cracking is widely used today to reduce heavy hydrocarbons into lighter and more useful products. One commonly used cracking catalyst is a type of crystalline inorganic synthetic products called “Y zeolites.” The Y zeolites typically contain silica having discrete pores in the range 6.5 to 13.5 Å. The Y zeolites also have higher surface area and acidity as compared to other types of catalyst such as amorphous silica-alumina based catalysts. As a result, Y zeolites can generate improved catalytic activity and selectivity towards gasoline.
When preparing Y zeolites, retaining catalytic activity can be difficult. For example, the Y zeolites can be sensitive to extreme pH conditions and other process conditions. Current solutions include using basic phosphate source to improve catalytic activity of the catalyst, but at the same time, attrition resistance of the catalyst has to be sacrificed. Hence, there is a need to develop a process for maintaining catalytic activity of high silica zeolites without sacrificing attrition resistance and apparent bulk density (ABD) of resulting catalyst.
U.S. Pat. No. 3,847,793 describes a process for conversion of hydrocarbons with a dual cracking component catalyst comprising ZSM-5 zeolite based catalyst and large pore zeolite based catalyst.
U.S. Pat. No. 6,258,257 refers to a process for producing polypropylene from C3 olefins by a two-stage fluid catalytic cracking process having two types of catalysts made from zeolites of large pore and medium pore.
U.S. Pat. No. 6,137,022 discloses a process of making an olefin product from an oxygenated feedstock by contacting the feedstock in a reaction zone containing 15 volume percent or less of a catalyst, preferably a catalyst comprising a silica-alumina-phosphate molecular sieve.
EP 0167325A3 relates to higher make-p of catalyst that may contain 2 or 3 times the amount of ZSM-5 sought for the equilibrium catalyst.
U.S. Pat. No. 6,156,947 refers to a process for jointly producing butene-1 and ether in a catalytic distillation column, which comprises an upper catalytic zone for etherification and a lower catalytic zone for isomerization of C3 to C4 olefins and conversion of butadiene.
U.S. Pat. No. 5,997,728 refers to a process for catalytically cracking of a heavy feed in a FCC unit, with large amounts of shape selective cracking additive. The catalyst inventory preferably contains at least 10 wt % additive, of 12-40% ZSM-5 on an amorphous support, equivalent to more than 3.0 wt % ZSM-5 crystal circulating with equilibrium catalyst. This process yields large amount of light olefins, without excessive production of aromatics, or loss of gasoline yield.
U.S. Pat. No. 4,309,280 describes a process for maximizing of LPG by adding very small amounts of powdered, neat ZSM-5 catalyst, characterized by a particle size below 5 microns to the FCC catalyst inventory.
U.S. Pat. No. 5,190,902, CA2156607A1 and CP 0643621B1 refer to a processes for the preparation of attrition resistant hinder particles by spray drying of clay phosphate slurry and ZSM-5 zeolite with adjusted extreme pH conditions, calcination.
U.S. Pat. No. 5,286,369 describes a aluminum phosphate binder for binding various zeolites, prepared by reaction between aluminum nitrate and phosphoric acid, while 3HNO3 is a undesired product detrimental to zeolite performance.
U.S. Pat. No. 4,803,185 is directed to providing an octane boosting catalyst containing a composite of an intermediate pore non-zeolitic molecular sieve (NZMS) in combination with another non-zeolitic molecular sieve having the same framework structure.
U.S. Pat. No. 4,522,705. Octane and total yield improvement in catalytic cracking of petroleum fractions under cracking conditions can be obtained by adding to conventional cracking catalysts small amounts of an additive catalyst comprising a class of zeolites characterized by a silica to alumina mole ratio greater than 5 and a Constraint Index of 1 to 12 wherein the zeolite additive catalyst is prepared via in-situ crystallization of preformed aggregates.
U.S. Pat. No. 4,549,956 refers to a Addition of AgHZSM-5 to conventional cracking catalysts results in a significant increase in gasoline octane without undue loss in gasoline yield. This octane increase is greater than could be achieved by adding HZSM-5.
U.S. Pat. No. 4,614,578 refers to octane and total yield improvement in catalytic cracking processes by the addition to conventional cracking catalysts of very small amounts of additive catalyst comprising a class of zeolites characterized by silica to alumina mole ratio greater than about 12 and a constraint index of about 1 to 12. The additive catalyst is added to the conventional cracking catalyst in the cracking process in an amount which provides the zeolite component of the additive catalyst at from about 0.01 weight percent to about 1.0 weight percent of the conventional cracking catalyst in the cracking process.
U.S. Pat. No. 4,784,745 relates to a catalyst and a process for enhancing gasline octane number of gasoline, wherein said shape-selective zeolite is selected from the group having the structure of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-34, ZSM-35, ZSM-38, ZSM-48, ZSM-50, TMA Offretite and Erionite.
U.S. Pat. No. 4,818,738 relates to a octane and improvement in catalytic cracking processes by the addition to conventional cracking catalysts of small amounts of additive catalyst comprising a class of zeolites characterized by a silica to alumina mole ratio greater than about 12 and a Constraint Index of about 1 to 12 bound in a matrix chosen such that the matrix component forms a thermodynamically favored compound with selected cations. Sustained catalytic activity is achieved by pre-exchanging the catalyst to a high level of selected cation loading.
U.S. Pat. No. 4,828,679 relates to octane and total yield improvement in catalytic cracking of petroleum fractions under cracking conditions by adding to conventional cracking catalysts small amounts of an additive catalyst comprising a class of zeolites characterized by a silica to alumina mole ratio greater than 12 and a constraint index of 1 to 12 wherein the zeolite additive catalyst has a crystal size of between 0.2 to 10 microns.
U.S. Pat. No. 4,867,863 deals with a Resid catalytic cracking process utilizing ZSM-5 for increased gasoline octane.
U.S. Pat. No. 4,927,523 relates to a method of adding an additive zeolite having a constraint index of 1-12 to a catalytic cracking unit wherein a heavy feed is added at a given feed rate to a catalytic cracking unit and contacts a source of hot, regenerated equilibrium catalytic cracking catalyst to produce cracked products including gasoline having an octane number.
U.S. Pat. No. 4,927,526 refers to a modified ZSM-5 type zeolite catalyst prepared by controlled aging in a moving bed catalytic cracking unit. The modified catalyst exhibits significant olefin isomerization activity and reduced paraffin cracking activity.
U.S. Pat. No. 4,983,276 refers to a process with increased octane number and increased C5+ gasoline content by employing a cracking catalyst composition containing both a large pore crystalline zeolite component and an MCM-22 zeolite component.
U.S. Pat. No. 4,997,545 relates to a process for the catalytic cracking of hydrocarbon oil feed which comprises contacting said feed under catalytic cracking conditions with a cracking catalyst in the presence of an additive comprising a basic nitrogen compound, to effect a shift in yield distribution from a maximum gasoline mode to a maximum middle distillate mode of operation.
U.S. Pat. No. 5,039,640 refers to a catalyst composition comprising of large pore crystalline molecular sieve component and an MCM-22 zeolite for catalytic cracking of a hydrocarbon oil to provide a product of increased octane number and increased C5+ gasoline content.
U.S. Pat. No. 5,051,164 connects to catalyst compositions of inorganic oxide bound shape-selective porous crystalline silicates for improved hydrothermal stability and octane enhancement prepared by adding binder precursors to a porous crystalline silicate reaction mixture which contains unincorporated silica, in-situ formed porous crystalline silicate and water.
U.S. Pat. No. 5,055,437 deals with multi-component catalyst mixture having Ga in ZSM-5 and process for catalytic cracking of heavy hydrocarbon feed to lighter products.
U.S. Pat. No. 5,151,394 refers to a catalyst composition comprising a catalytic molecular sieve material and a matrix material comprising boron phosphate compound.
U.S. Pat. No. 5,302,567 relates to a FCC catalyst additive for the catalytic cracking of hydrocarbons wherein said catalyst comprises a conventional cracking catalyst dispersed in an inorganic matrix and a zeolite additive composition comprising a medium-pore zeolite selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, and ZSM-38 to improve the octane number of the gasoline-range product of an FCC process.
U.S. Pat. No. 5,348,643, relates to a process for converting feedstock hydrocarbon compounds over a catalyst composition comprising clay and a zeolite component, at least one of which has been treated with a phosphorus-containing compound, which is spray dried at a low pH, to produce high octane gasoline and increased lower olefins, especially propylene and butylene.
U.S. Pat. No. 5,372,704 relates to a process and apparatus for low cracking or recracking of liquid hydrocarbons with FCC catalyst containing 0.2 to 1.5 wt % coke.
U.S. Pat. No. 5,779,882 refers to a layered composition from modified MCM-56 to offer improved gasoline yield/octane relationship, an improved coke selectivity and a higher combined gasoline and potential alkylate yield than an identical catalyst containing unmodified MCM-56 of matter.
U.S. Pat. No. 5,846,402 relates to a process for selective catalytic cracking of a petroleum-based feedstock to produce a product having a high yield of liquified petroleum gas (LPG) and light olefins having 3 to 4 carbons.
U.S. Pat. No. 5,997,728, refers to a process for cracking of heavy feed in an FCC unit, to enhance light olefins, without excessive production of aromatics, or loss of gasoline yield with large amounts of shape selective cracking additive preferably at least 10 wt % additive, of 12-40% ZSM-5 on an amorphous support, equivalent to more than 3.0 wt % ZSM-5 crystal circulating with equilibrium catalyst.
U.S. Pat. No. 6,613,710 deals with a process for preparing bi-functional catalyst comprising of molecular sieves, modified clay and semi-basic alumina for effective cracking of high boiling petroleum feedstock to provide simultaneously, enhanced yields of Liquefied Petroleum Gas (LPG) and reduction of undesirable bottoms.
U.S. Pat. No. 6,677,263, discloses a catalytic promoter comprising of 5-65 wt % of modified HZSM-5 zeolite with Zn, P, Ga, Al, Ni and rare earth elements in an amount 0.01-10.37 wt % based on total weight of HZSM-5 zeolite to increase gasoline octane number and an increased lower olefin yield.
U.S. Pat. No. 7,459,413 discloses a catalyst and a process for its preparation and its use in cracking heavy feedstocks. The catalyst comprises one or more zeolites having controlled silica to alumina ratio and preferably treated with alkali in the presence of a matrix component selected from the group consisting of clays, synthetic matrix other than pillared clay, and mixtures thereof. The catalyst is particularly useful in treating heavy feedstock such as residues from oil sands processing.
U.S. Pat. No. 7,485,595 discloses a molecular sieve-containing catalyst for cracking hydrocarbons, comprising molecular sieve, refractory inorganic oxide, clay and a metal component, wherein the amount of said molecular sieve is from 1 to 90% by weight, the refractory inorganic oxide is from 2 to 80% by weight, the clay is from 2 to 80% by weight, and the metal component is from 0.1 to 30% by weight, calculated as the oxide of said metal having its maximum valence state, based on the total amount of the catalyst, wherein said metal component exists essentially in a reduction state and is one or more metals selected from the group consisting of metals of Group IIIA (other than aluminum), and metals of Group IVA, VA, IB, IIB, VB, VIB and VIIB, and non-noble metals of Group VIII of the periodic table. The catalyst has higher cracking activity and higher sulfur reduction activity.
U.S. Pat. No. 7,517,827 relates to a cracking catalyst composition for cracking heavy hydrocarbon and processes for preparing the catalyst. The process can include treating zeolite with sodium free basic compound with or without phosphate, treating an alumina with a dilute acid, acidifying a colloidal silica, preparing a fine slurry of clay with a source of phosphate, adding alumina slurry and/or acidified colloidal silica to clay phosphate slurry, adding treated zeolite and spray-drying the slurry and calcining the same to obtain a cracking catalyst having adequate ABD and attrition resistance property.
U.S. Pat. No. 9,278,342 discloses a method of modifying a phosphorus-treated zeolite catalyst is carried out by contacting an unbound and calcined phosphorus-treated pentasil zeolite with water in a water treatment wherein at least a portion of the water is in a liquid phase. The water treatment is sufficient to remove at least 80% by weight or more of phosphorus from the phosphorus-treated zeolite and provide an increase in the pore volume of the zeolite by at least 50% prior to the water treatment to form a modified phosphorus-treated zeolite catalyst. A zeolite catalyst is also provided in the form of a phosphorus-containing pentasil zeolite having a phosphorus content of 7.5% or less by weight of zeolite and a 27Al MAS NMR peak at 50 ppm that is greater than any other 27Al MAS NMR and a pore volume of 0.2 ml/g or more.
The ZSM-5 additive described in the above prior art use phosphate to stabilize the acid sites of ZSM-5 zeolite as well as acts as a binder to improve the Apparent Bulk Density (ABD) and Attrition Resistance (AI) of ZSM-5 additive. Therefore during preparation of ZSM-5 additive, always there will be presence of excess phosphate in the final additive formulation which has a detrimental effect on active component of Y zeolite present in the FCC catalyst.
None of the above prior arts disclose removal of excess phosphate present in the additive formulation which has a detrimental effect on active component of Y zeolite present in the FCC catalyst to improve high value product selectivity.